WinJS.Promise#as is not what you think it is, use wrap instead - fixes #11754

extensions/vscode-api-tests/src/window.test.ts

@@ -232,6 +232,20 @@ suite('window namespace tests', () => {
 		return result;
 	});
 
+	test('showQuickPick, native promise - #11754', function () {
+
+		const data = new Promise<string[]>(resolve => {
+			resolve(['a', 'b', 'c']);
+		});
+
+		const source = new CancellationTokenSource();
+		const result = window.showQuickPick(data, undefined, source.token);
+		source.cancel();
+		return result.then(value => {
+			assert.equal(value, undefined);
+		});
+	});
+
 	test('editor, selection change kind', () => {
 		return workspace.openTextDocument(join(workspace.rootPath, './far.js')).then(doc => window.showTextDocument(doc)).then(editor => {
 

src/vs/base/common/winjs.base.d.ts

@@ -85,6 +85,10 @@ export declare class TPromise<V> {
 	public static join<ValueType>(promises:Thenable<ValueType>[]):Thenable<ValueType[]>;
 	public static join<ValueType>(promises: {[n:string]:TPromise<ValueType>}):TPromise<{[n:string]:ValueType}>;
 	public static any<ValueType>(promises:TPromise<ValueType>[]):TPromise<{ key:string; value:TPromise<ValueType>;}>;
+
+	public static wrap<ValueType>(value: Thenable<ValueType>): TPromise<ValueType>;
+	public static wrap<ValueType>(value: ValueType): TPromise<ValueType>;
+
 	public static wrapError<ValueType>(error:any):TPromise<ValueType>;
 }
 

src/vs/workbench/api/node/extHostQuickOpen.ts

@@ -29,7 +29,7 @@ export class ExtHostQuickOpen extends ExtHostQuickOpenShape {
 		// clear state from last invocation
 		this._onDidSelectItem = undefined;
 
-		const itemsPromise = <TPromise<Item[]>> TPromise.as(itemsOrItemsPromise);
+		const itemsPromise = <TPromise<Item[]>>TPromise.wrap(itemsOrItemsPromise);
 
 		const quickPickWidget = this._proxy.$show({
 			autoFocus: { autoFocusFirstEntry: true },